1. Field of the Invention
The invention relates to a process for the production of a water-insoluble nitrogenous organic base, for example an amine, from an aqueous solution of an alkali metal bicarbonate and the hydrochloride of the said nitrogenous organic base.
2. Description of the Art
A method for the manufacture of potassium or sodium bicarbonate is known, according to which an aqueous solution of potassium or sodium chloride is mixed with an organic solution of a water-insoluble amine, the resultant mixture is treated with a gas containing carbon dioxide and is then subjected to gravity separation to separate an aqueous suspension of potassium or sodium bicarbonate from an organic solution of amine hydrochloride, the aqueous suspension is treated to separate off the solid potassium or sodium bicarbonate which it contains from a mother liquor and the amine is regenerated from the organic solution of amine hydrochloride (Patent GB-A-1,082,436 (Kaiser Aluminum & Chemical Corporation), page 2, line 105 to page 3, line 5; Central Patents Index, Basic Abstracts Journal, Section E, Week T.49, Derwent Publications Ltd., London, Abstract 78430T-E: Patent Application JP-A-7241237 (Israel Mining Ind. Inst. Res. & Dev.)).
In the description which follows the expression "amines method" will refer to this known method for the manufacture of potassium or sodium bicarbonate.
In this known method it can happen that the mother liquor, saturated with alkali metal bicarbonate, also contains dissolved amine hydrochloride. This is the case particularly when the amine employed is triethylamine or a primary alkylamine containing fewer than 18 carbon atoms in its molecule, such as that known under the tradename Primene 81R (Rohm & Haas), which contains approximately 12 to 14 carbon atoms in its molecule. In a known amines method which employs triethylamine the mother liquor is treated with a basic agent (calcium hydroxide) to decompose the amine hydrochloride which is dissolved in it and the amine is collected (Patent IL-A-33,551 (IMI (TAMI) Institute for Research and Development), page 8, Example 3). This known process for regenerating the amine involves an excessive consumption of basic agent, a considerable part of which is in fact consumed uselessly to decompose the sodium bicarbonate in the mother liquor.